Overuse of organ biopsies in immunoglobulin light chain (AL) amyloidosis: The consequence of failure of early recognition.

Abstract

e19532 Background: The diagnosis of amyloidosis requires histological confirmation of Congo-red (CR) deposits. The tissue source is preferably fat and/or bone marrow biopsy, but at times organ biopsy is required. Methods: We studied 612 patients with systemic light chain amyloidosis to characterize the tissues used to establish the diagnosis Results: The median number of tissue samples biopsied for CR staining was 3. Ninety-five percent of bone marrow (BM) biopsies were stained for CR, while 79% of patients had fat aspiration performed for CR staining. Overall, 76% of patients underwent both procedures. CR stain sensitivity was 69% in BM samples, 75% in fat aspiration and in 89% for both sources combined. CR stain sensitivity was 97-100% for heart, renal and liver biopsies. 42% of patients with renal involvement, 21% of patients with liver involvement and 13% of patients with heart involvement underwent organ biopsy, when a less invasive safer biopsy would have established the diagnosis. Predictors of need for organ biopsy were male sex, limited organ involvement and lack of fat aspiration (Table). Conclusions: Fat aspiration is underutilized for histologic confirmation of amyloidosis. Organ biopsies (particularly renal biopsies) were performed at a high rate, which represents a failure to recognize the disease (i.e. failure to screen with a light chain assay etc.). Early awareness of amyloidosis in the differential diagnosis of patients with organ dysfunction may lead to fewer unnecessary organ biopsies [Table: see text]